KR20190099062A - Carbon nanoparticle-porous framework composites, composites of carbon nanoparticle-porous framework composites with lithium metals, methods for their preparation and uses thereof - Google Patents

Abstract

Carbon nanoparticle-porous framework composites, lithium metal composites of the carbon nanoparticle-porous framework composites, methods of making the same, and uses thereof are provided. In the carbon nanoparticle-porous framework composite material, the porous framework is a carbon-based porous microsphere material with a diameter of 1 μm to 100 μm, or a porous metal material having internal pores with a microscale pore size distribution; Carbon nanoparticles are distributed within or on the pores of this carbon-based porous microsphere material or porous metal material. The carbon nanoparticle-porous framework composite material is mixed with molten lithium metal to form a lithium-carbon nanoparticle-porous framework composite material. The carbon nanoparticles present in the material can better conduct lithium ions during battery recycling, thereby inhibiting lithium metal dendrite production and improving battery safety and recycling stability.

Description

Carbon nanoparticle-porous framework composites, composites of carbon nanoparticle-porous framework composites with lithium metals, methods for their preparation and uses thereof

The present invention relates to nanocomposites, in particular carbon nanoparticle-porous skeletal composites, composites thereof comprising lithium metal, methods for their preparation, and uses.

Lithium batteries are widely used in applications such as home appliances, electric vehicles and energy storage devices due to their high specific energy and long life. In existing lithium batteries, compounds containing lithium elements are used as positive electrodes, and graphite is used as negative electrodes. However, graphite-based negative electrode materials have a specific capacity limit of about 370 mAh / g. It is difficult to further increase the energy density of lithium batteries using such negative electrode materials, and these negative electrode materials are hardly able to meet the market demand for higher energy density lithium batteries. Because the specific capacity of the metal lithium negative electrode is large (3860 mAh / g) and the electrode potential is low (-3.04 V for the standard hydrogen electrode (SHE)), these lithium batteries show large specific energy, long life and high voltage. It can be widely used in such fields as home appliances, electric vehicles and energy storage devices. The metal lithium negative electrode has several advantages of high specific capacity (3860 mAh / g), low electrode potential (at -3.04 V for SHE), and low density (at 0.59 g / cm ³ ). Lithium batteries using lithium as the negative electrode can have a significantly improved energy density. On the other hand, lithium ions can be provided when metal lithium is used as the negative electrode of the battery, and as a result, a lithium-free material having a higher capacity, such as sulfur and air, can be used as the positive electrode.

However, in batteries with metallic lithium negative electrodes, dendrites and "dead lithium" are produced during the cycle, resulting in reduced coulombic efficiency and reduced lifespan. More importantly, as the dendrites grow, holes in the separator can form, causing internal short circuits between the positive and negative electrodes that are connected to each other, generating large amounts of heat, burning or even exploding the battery. Can be. These problems have extremely limited the use of metallic lithium negative electrodes in recent decades.

The main object of the present invention is to provide a carbon nanoparticle-porous skeleton composite material, a composite thereof having a lithium metal, a method for preparing the same, an electrode, in order to improve the safety and / or cycle stability of a battery by suppressing the generation of metallic lithium dendrites. And to provide an electrochemical battery comprising such an electrode.

Embodiments of the present invention include the following.

In some embodiments, the porous backbone is a carbon-based porous microsphere material with a diameter of 1 μm to 100 μm, or a porous metal material having internal pores with a pore size distribution of micrometer scale, and the carbon nanoparticles are carbon-based porous A carbon nanoparticle-porous skeletal composite material is provided that is distributed on the inside and the surface of the microsphere material or porous metal material.

In some embodiments, dispersing carbon nanotubes or carbon nanofibers in a solvent with carbon nanoparticles to produce a dispersion, and then spray drying the dispersion; Or immersing microscale porous graphite, mesocarbon microspheres, porous activated carbon, or porous metal material in a solution containing carbon nanoparticles, followed by sonication, and then drying the resultant. A method for producing a carbon nanoparticle-porous backbone composite material is provided.

In some embodiments, the lithium-carbon nanoparticle-porous material comprising the carbon nanoparticle-porous skeleton composite material described above, wherein metal lithium is dispersed and contained within and within the voids of the carbon nanoparticle-porous framework composite material. Skeletal composite materials are provided.

In some embodiments, a method of preparing a metal lithium-carbon nanoparticle-porous skeleton composite material, comprising mixing molten lithium metal with the carbon nanoparticle-porous skeleton composite material described above and then cooling the mixture. A method is provided.

In some embodiments, an electrode is provided that includes the lithium-carbon nanoparticle-porous framework composite material described above.

In some embodiments, as an electrochemical energy storage device comprising the electrode described above, an electrochemical energy storage device comprising an electrochemical battery or super capacitor is provided.

The present invention has at least one of the following advantageous effects:

(1) When the carbon nanoparticle-porous skeleton composite material is mixed with molten lithium metal, a lithium-carbon nanoparticle-porous skeleton composite material can be produced. Carbon nanoparticles present in the material can better conduct lithium ions during the battery cycle.

(2) Lithium-carbon nanoparticle-porous skeleton composite material can be used as negative electrode of battery, which can improve cycle stability of battery.

(3) The manufacturing method is simple and suitable for mass production.

(4) Metal lithium-carbon nanoparticle-porous framework composites can be used in various lithium batteries, and can be used in metal lithium-oxide batteries, metal lithium-polymer batteries and rechargeable lithium ion batteries.

1 shows scanning electron microscope (SEM) images of acetylene black-carbon nanotube microsphere composites (a, b) and lithium-carbon composite microparticles (c, d) obtained in Example 1. FIG.
FIG. 2 is an enlarged view of the SEM image b of FIG. 1 (magnification: 20,000 times).
FIG. 3 shows a half-cell made of lithium-carbon composite microparticles of Example 1 and a half cell made of a lithium sheet, each having a current density of 0.5 mA · cm ⁻² and a capacity of 0.5 mAh · cm. The half cell cycle performance test results performed under the condition of ⁻² are shown.
Fig. 4 shows a half cell made of the lithium-carbon composite microparticles of Example 1 and a half cell made of a lithium sheet after 200 cycles under conditions of a current density of 0.5 mA · cm ⁻² and a capacity of 0.5 mAh · cm ⁻² . Each electrode morphology is shown (a and b show images of lithium-carbon composite microparticles, c and d show images of lithium sheets).
5 shows the voltage-capacity curves of the lithium-carbon composite microparticle / lithium halfcell of Example 1 in different cycles during the constant current charge-discharge test.
FIG. 6 shows the C-rate (C) at different cycles for each of the full cells of lithium-carbon composite microparticles and lithium iron phosphate of Example 1 and the full cells of lithium sheet and lithium iron phosphate. shows the result of the capacity retention test when -rate) is 1.
FIG. 7 shows a comparison of microsphere materials made of carbon nanoparticles and microsphere materials prepared without using carbon nanoparticles, and the left image shows the microsphere material obtained in Example 2. FIG. Image, and the right image is the microsphere image obtained in Example 1.
FIG. 8 shows a half cell made of the lithium-carbon composite microparticles of Example 2 and a half cell made of the lithium sheet under conditions of a current density of 0.5 mA · cm ⁻² and a capacity of 0.5 mAh · cm ⁻² . It shows the results of the half-cell cycle characteristic test performed.
9 shows an SEM image of the lithium-carbon fiber microsphere composite material of Example 5. FIG.
FIG. 10 shows a constant current charge-discharge curve when the lithium-carbon fiber microsphere composite of Example 5 is a negative electrode.
FIG. 11 shows the results of a half cell cycle characteristic test conducted under the conditions of a current density of 0.5 mA · cm ⁻² and a capacity of 0.5 mAh · cm ⁻² for a half cell made of the metal lithium-nickel skeleton material of Example 6 will be.
FIG. 12 shows the capacity retention test results when the C-rate is 1 in different cycles for a full cell consisting of the metal lithium-nickel skeleton material of Example 6 and lithium iron phosphate.

Carbon Nanoparticle-porous Skeletal Composites :

One aspect of the invention includes a porous skeleton consisting of a carbon-based porous microsphere material having a diameter of 1 μm to 100 μm, or a porous metal material having internal pores having a pore size distribution of micrometer scale, wherein the carbon nanoparticles are Provided are carbon nanoparticle-porous skeletal composite materials distributed over and within the voids of a porous skeletal material.

In some embodiments, the carbon-based porous microsphere material comprises at least one selected from the group consisting of carbon nanotubes or carbon nanofiber microsphere materials, graphite, mesocarbon microspheres, and porous activated carbon.

In some embodiments, the carbon nanotubes or carbon nanofiber microsphere materials are prepared by intertwining and binding the thixo nanotubes or carbon nanofibers together, wherein a plurality of nanoscale pores are formed on its surface and on its surface. exist. These microspheres have a solid structure (similar to the weaving structure). In other words, the microspheres are filled with carbon nanotubes or carbon nanofibers therein. However, nanoscale pores exist between the bonded carbon nanotubes or carbon nanofibers, which can be used to accommodate carbon nanoparticles and metallic lithium particles.

In some embodiments, the carbon nanotubes or carbon nanofiber microsphere materials are spherical or spheroidal particles. The average diameter of these particles is from 1 μm to 100 μm, preferably from 1 μm to 25 μm, and the specific surface area is from 100 m ² / g to 1500 m ² / g, preferably from 150 m ² / g to 500 m ² /. g may be. The pore size distribution of the pores contained in the microspheres can be 1 nm to 200 nm, preferably 1 nm to 50 nm. Microspheres containing carbon nanoparticles are not significantly different from microspheres containing no carbon nanoparticles in terms of morphology and structure, but the pore volume is smaller (for example, the pore volume is 2.0 cm ³ · g ⁻¹ to 1.4 cm ³ · g ⁻¹ ).

In some embodiments, the carbon nanotube or carbon nanofiber microsphere material is any selected from the group consisting of at least a coherent structure of a spherical entity, a spherical cohesion structure, a spheroidal cohesion structure, a porous spherical cohesion structure, and a toroidal cohesion structure Has one of

In some embodiments, the carbon nanotubes comprise any one selected from the group consisting of multiwall carbon nanotubes, double wall carbon nanotubes and single wall carbon nanotubes, or a combination of two or more thereof, and optionally carbon Nanotubes are subject to surface functionalization treatment. The group which alters the surface of the carbon nanotubes may be selected from -COOH, -OH, -NH ₂ groups, and the like, but is not limited thereto.

In some embodiments, the graphite, mesocarbon microspheres and porous activated carbon are sheet like, spherical or spheroidal particles. The average diameter of these particles is from 50 μm to 500 μm, preferably from 100 μm to 200 μm and the specific surface area is from 100 m ² / g to 1000 m ² / g, preferably from 100 m ² / g to 500 m ² /. g. The pore size distribution of the contained pores may be 20 nm to 500 nm, preferably 20 nm to 100 nm.

In some embodiments, the porous metal material includes at least one selected from the group consisting of porous copper, porous aluminum, porous zinc, porous iron, porous nickel, porous gold, and porous silver.

In some embodiments, the pore size distribution of the pores contained in the porous metal material may be between 100 μm and 1000 μm, preferably between 100 μm and 500 μm; The specific surface area may be 50 m ² / g to 500 m ² / g, preferably 50 m ² / g to 200 m ² / g.

In some embodiments, the carbon nanoparticles comprise at least one selected from the group consisting of carbon black (such as Degussa carbon black), acetylene black, Ketjen black, Timcal conductive additive Super P, and Cabot BP2000.

In some embodiments, the size of the carbon nanoparticles may be between 1 nm and 500 nm, preferably between 50 nm and 200 nm.

In some embodiments, the content of carbon nanoparticles in the carbon nanoparticle-porous framework composite material may be 20 wt% to 500 wt%, preferably 50 wt% to 200 wt%, based on the porous skeleton.

Method for preparing carbon nanoparticle-porous skeletal composite material :

Another aspect of the present invention is to prepare a dispersion by dispersing carbon nanotubes or carbon nanofibers in a solvent together with carbon nanoparticles, and then spray drying the dispersion; Or immersing the microscale porous graphite, mesocarbon microspheres, porous activated carbon, or porous metal material in a solution containing carbon nanoparticles, followed by sonication, and then drying the resultant carbon nanoparticles. A method for producing a porous skeletal composite material is provided.

In some embodiments, carbon nanoparticle-carbon nanotubes or carbon nanofiber microsphere composites can be prepared by spray drying methods. For example, the production method may comprise the following steps, namely

a. Dispersing the carbon nanotubes / carbon nanofibers and carbon nanoparticles in a dispersion solvent (without surfactant) through sonication to obtain a dispersion;

b. Spraying the dispersion obtained in step a through the nozzle of a spray dryer which has a predetermined air inlet temperature and an air outlet temperature, provided that the dispersion is continuously stirred while spraying takes place; And

c. Cooling to obtain carbon nanoparticle-carbon nanotube / carbon nanofiber microsphere composites

It may include.

In some embodiments, the mass ratio between carbon nanoparticles and carbon nanotubes / carbon nanofibers in step a is from 0.5: 1 to 8: 1, preferably from 0.5: 1 to 5: 1, more preferably from 0.5: 1 to 2: 1.

For "carbon nanoparticles" and "carbon nanotubes / carbon nanofibers", reference may be made to those described in this section in the "Carbon nanoparticle-porous framework composites" section above.

In some embodiments, the concentration of carbon nanotubes / carbon nanofibers in the dispersion may be 10 g / L to 50 g / L, preferably 10 g / L to 15 g / L.

In some embodiments, the solvent is an organic and / or inorganic liquid capable of uniformly dispersing carbon nanotubes / carbon nanofibers and carbon nanoparticles such as water, aqueous ammonia, hydrochloric acid solution, ethanol, acetone and isopropanol Or any one selected from the group consisting of a combination thereof can be used.

In some embodiments, the solvent can be a mixture of ethanol and water (volume ratio 1:10).

In some embodiments, the spray drying conditions may include the following: air inlet temperature of 150 ° C. to 250 ° C. and air outlet temperature of 75 ° C. or higher, such as 75 ° C. to 150 ° C., or 90 ° C. or higher. One preferred condition for spray drying includes air inlet temperatures of 190 ° C to 210 ° C and air outlet temperatures of 90 ° C to 110 ° C.

In some embodiments, the spray rate during spray drying can be between 1 mL / min and 100 L / min.

In some embodiments, micro-scale porous graphite, mesocarbon microspheres, porous activated carbon, or porous metal materials are used as the porous framework material, and carbon nanoparticle-porous framework composite materials are prepared by using impregnation and sonication methods. Impregnation and sonication methods may include immersing microscale porous graphite, mesocarbon microspheres, porous activated carbon, or a porous metal material in a carbon nanoparticle solution, sonicating, and then drying the resultant.

In some embodiments, the carbon nanoparticle solution comprises a solution containing carbon nanoparticles in water or an ethanol solvent, or a mixed solvent of ethanol and water.

In some embodiments, the concentration of carbon nanoparticles in the carbon nanoparticle solution may be between 5 g / L and 50 g / L, preferably between 10 g / L and 30 g / L.

Metal Lithium-Carbon Nanoparticles-Porous Skeletal Composites

Another aspect of the present invention includes a metal lithium-carbon nano, including the above-described carbon nanoparticle-porous skeleton composite material, wherein metal lithium is distributed within and on the surface of the voids of the carbon nanoparticle-porous skeleton composite material. As a particle-porous skeletal composite material, the carbon nanoparticle-porous skeletal composite material, which is a skeleton, supports metal lithium, which is mainly present in the voids or surfaces thereof (mainly inside the voids and only slightly on the surfaces) of the composite material. Metal lithium-carbon nanoparticle-porous skeleton composite material present in the form of an elemental component).

In some embodiments, the metallic lithium is present from 1% to 95% by mass, preferably from 10% to 70% by mass, and more preferably from 20% to 70% by mass of the total mass of the composite material.

Method for Producing Metal Lithium-Carbon Nanoparticle-Porous Skeletal Composites

Another aspect of the invention provides a process for preparing a metal lithium-carbon nanoparticle-porous skeleton composite material comprising mixing molten lithium metal with the carbon nanoparticle-porous skeleton composite material described above and then cooling the mixture. It provides a method for doing so.

In some embodiments, the step of mixing the molten lithium metal and the carbon nanoparticle-carbon based porous microsphere material may include mixing the lithium metal and the carbon based porous microsphere material with stirring and then heating. .

In some embodiments, the mixing with stirring may comprise a preliminary stirring step and a rapid stirring step, provided that the preliminary stirring step is performed at a slow rate (eg, about 50) of the mixture of lithium metal and carbon nanoparticle-porous framework composite material. stirring at a relatively low temperature (eg, from about 200 ° C. to about 230 ° C.) for a short period of time (eg, 1 minute to 5 minutes) at rpm to about 100 rpm, wherein the rapid stirring step is performed at a high speed (eg, about 150 rpm to about Stirring at 1000 rpm, preferably 200 rpm to 800 rpm, at a relatively high temperature (eg, about 230 ° C. to about 300 ° C.).

For “carbon based porous microsphere materials”, reference may be made to what is described in this regard in the “Carbon Nanoparticle-Porous Skeletal Composite Materials” section above.

In some embodiments, the step of mixing the molten lithium metal and the carbon nanoparticle-porous metal composite material may include immersing the carbon nanoparticle-porous metal composite material in the molten lithium metal.

In some embodiments, the metallic lithium is present from 1% to 95% by mass, preferably from 10% to 70% by mass, and more preferably from 20% to 70% by mass of the total mass of the composite material.

Uses of Metal Lithium-Carbon Nanoparticle-Porous Skeletal Composites

Another aspect of the present invention provides an electrode comprising the above-described metal lithium-carbon nanoparticle-porous skeleton composite material as an electrode material.

In some embodiments, the metal lithium-carbon nanoparticle-porous skeleton composite material can be used as a negative electrode active material of a battery, or can be used as a direct electrode (when a porous metal skeleton is used).

Another aspect of the invention provides an electrochemical energy storage device comprising the electrode described above.

In some implementations, the electrochemical energy storage device is an electrochemical battery and the electrode is used as the negative electrode of this battery.

In some embodiments, the electrochemical battery includes a lithium battery, a metal lithium-oxide battery, a metal lithium-sulfur secondary battery, or a metal lithium-air battery.

In some implementations, the electrochemical energy storage device is a super capacitor and the electrode is used as one pole plate of this super capacitor.

When the lithium-carbon nanoparticle-porous skeletal composite material provided in the present invention is used in an electrochemical battery, the carbon nanoparticles present in this material better conduct lithium ions during the battery cycle, thereby inhibiting lithium dendrite production and In addition to improving the safety of the battery, the cycle stability of the battery may also be improved.

The following specific embodiments are intended to illustrate, but not to limit the invention.

Embodiment 1 is a carbon-based porous microsphere material with a porous backbone having a diameter of 1 μm to 100 μm, or a porous metal material having internal pores with a pore size distribution of micrometer scale, wherein the carbon nanoparticles are carbon-based porous microspheres It is a carbon nanoparticle-porous skeletal composite material, distributed on the interior and surface of the pores of a material or porous metal material.

Embodiment 2 includes a carbon nanotube comprising at least one carbon-based porous microsphere material selected from the group consisting of carbon nanotubes or carbon nanofiber microsphere materials, graphite, mesocarbon microspheres, and porous activated carbon. Alternatively, the carbon nanofiber microsphere material is prepared by intertwining and tying together tinso nanotubes or carbon nanofibers, and the microspheres are filled with carbon nanotubes or carbon nanofibers in their own interior, but inside and on the surface thereof. Multiple nano scale pores exist and / or exist;

The porous metal material comprises at least one selected from the group consisting of porous copper, porous aluminum, porous zinc, porous iron, porous nickel, porous gold and porous silver;

The carbon nanoparticles are carbon nanoparticle-porous skeleton composites according to embodiment 1, comprising at least one selected from the group consisting of carbon black, acetylene black, Ketjen black, Timcal conductive additive Super P, and Cabot BP2000. .

Embodiment 3 is the carbon nanoparticle-porous skeletal composite material according to embodiment 1 or 2, wherein the carbon nanoparticles may have a size of 1 nm to 500 nm, preferably 50 nm to 200 nm.

Embodiment 4 is the carbon nanoparticle-porous skeleton composite material according to any one of embodiments 1-3, wherein the carbon nanoparticle content is 20 wt% to 500 wt% based on the porous skeleton.

Embodiment 5 has a specific surface area of carbon nanotubes or carbon nanofiber microsphere materials of 100 m ² / g to 1500 m ² / g;

The pore size of the pores contained in the carbon nanotube or carbon nanofiber microsphere material is 1 nm to 200 nm;

The carbon nanotube or carbon nanofiber microsphere material has / has at least any one selected from the group consisting of at least microsphere-like aggregate structures, spherical aggregate structures, spheroidal aggregate structures, porous spherical aggregate structures, and donut-shaped aggregate structures. Or;

The carbon nanotubes comprise any one selected from the group consisting of multiwall carbon nanotubes, double wall carbon nanotubes and single wall carbon nanotubes, or a combination of two or more thereof, optionally wherein the carbon nanotubes are surface functionalized. A carbon nanoparticle-porous skeletal composite material according to any one of embodiments 2-4, which is the subject of treatment.

Embodiment 6 includes preparing a dispersion by dispersing carbon nanotubes or carbon nanofibers in a solvent together with carbon nanoparticles, and then spray drying the dispersion; or

Immersing microscale porous graphite, mesocarbon microspheres, porous activated carbon, or porous metal material in a solution containing carbon nanoparticles, followed by sonication, and then drying the resultant.

A method for producing a carbon nanoparticle-porous skeleton composite material according to any one of embodiments 1 to 5, comprising:

Embodiment 7 includes spray drying carbon nanotubes or carbon nanofibers with carbon nanoparticles in the following steps, i.e.

a. Dispersing the carbon nanotubes / carbon nanofibers and carbon nanoparticles in a dispersion solvent (without surfactant) through sonication to obtain a dispersion;

b. Spraying the dispersion obtained in step a through the nozzle of a spray dryer which has a predetermined air inlet temperature and an air outlet temperature, provided that the dispersion is continuously stirred while spraying takes place; And

c. Cooling the result to obtain carbon nanoparticle-carbon nanotube / carbon nanofiber microsphere composites

Including, a method according to embodiment 6.

Embodiment 8 includes the mass ratio between the carbon nanoparticles and the carbon nanotubes / carbon nanofibers in step a is from 0.5: 1 to 8: 1;

The concentration of carbon nanotubes / carbon nanofibers in the dispersion is 10 g / L to 50 g / L;

The dispersing solvent is the method according to embodiment 7, comprising any one selected from the group consisting of water, aqueous ammonia, hydrochloric acid solution, ethanol, acetone and isopropanol or combinations thereof.

Embodiment 9 has an air inlet temperature of 190 ° C. to 210 ° C. and an air outlet temperature of 90 ° C. to 110 ° C .;

The process according to embodiment 7 or 8, wherein the spray rate is from 1 mL / min to 100 L / min.

Embodiment 8 includes a solution comprising carbon nanoparticles comprises an aqueous solution containing carbon nanoparticles;

The method according to embodiment 6, wherein the concentration of carbon nanoparticles in the solution containing the carbon nanoparticles is from 5 g / L to 50 g / L.

Embodiment 10 includes a carbon nanoparticle-porous skeleton composite material according to any one of embodiments 1 to 5, wherein the metal lithium is distributed on and within the voids of the carbon nanoparticle-porous skeleton composite material. Metal lithium-carbon nanoparticle-porous skeleton composite material.

Embodiment 11 is the lithium-carbon nanoparticle-porous skeleton composite material according to embodiment 10, wherein the metal lithium is present from 1% to 95% by mass based on the total mass of the lithium-carbon nanoparticle-porous skeleton composite material. .

Embodiment 12 includes mixing a carbon nanoparticle-porous framework composite material according to any one of embodiments 1 to 5 with molten lithium metal and then cooling the mixture. A method for producing a porous skeletal composite material.

Embodiment 13 further comprises the step of mixing the molten lithium metal and carbon nanoparticle-carbon based porous microsphere composite

Mixing the lithium metal and the carbon-based porous microsphere material with stirring, followed by heating; or

The method according to embodiment 11, comprising immersing the carbon nanoparticle-porous metal composite material in molten lithium metal.

Embodiment 14 is the method according to embodiment 13, wherein the stirring and mixing comprises a preliminary stirring step and a rapid stirring step, provided that the preliminary stirring step is performed at 50 rpm of the mixture of the lithium metal and the carbon nanoparticle-porous skeleton composite material. It includes stirring for 1 minute to 5 minutes at 200 ℃ to 230 ℃ at a rate of to 100 rpm, the rapid stirring step is a method comprising a rapid stirring at 230 ℃ to 300 ℃ at a speed of 150 rpm to 1000 rpm .

Embodiment 15 is an electrode comprising the lithium-carbon nanoparticle-porous framework composite material according to embodiment 10 or 11.

Embodiment 16 is an electrochemical energy storage device comprising the electrode according to embodiment 15, wherein the electrochemical energy storage device comprises an electrochemical battery or a super capacitor.

Embodiment 17 is the electrochemical energy storage device according to embodiment 16, wherein the electrochemical battery comprises a lithium battery, a metal lithium-oxide battery, a metal lithium-sulfur secondary battery, or a metal lithium-air battery.

BRIEF DESCRIPTION OF DRAWINGS To make the objects, technical solutions and advantages of the present invention clearer and clearer, the present invention will be described in more detail below with reference to the drawings and embodiments. It is to be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to be limiting. In addition, the technical features accompanying the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

In addition, various structural parameters, various reactants and process conditions of the articles used and applied in the examples below are typical examples. However, the inventors can also apply, through a number of experiments, other structural parameters different from those listed above, other types of reactants, and other process conditions, and achieve the technical effects as stated in the present invention. It was confirmed.

Example  One

2 g of CHENGDU ORGANIC CHEMICALS CO. LTD.CHINESE ACADEMY OF SCIENCES with an outer diameter of 20 nm to 30 nm and 2 g of acetylene black (Alfa Aesar) were added to 200 mL of deionized water, 20 mL of ethanol was added. The mixture was sealed, stirred and sonicated with a 130 W ultrasonic probe for 5 hours to uniformly disperse the sample. The sample was then introduced to a spray drier. The air inlet temperature was set to 200 ° C., the air outlet temperature was set to 150 ° C., the injection pressure was set to 40 MPa, and the sample size was set to 500 mL / h. After drying, acetylene black-carbon nanotube microsphere composites were obtained. Nitrogen adsorption-desorption tests were performed on the composite material, and the results showed that the specific surface area of the microspheres was 103 m ² / g and the average pore size was 15.2 nm.

100 mg of battery-grade metal lithium and 100 mg of the acetylene black-carbon nanotube microsphere composite were weighed, placed in a heater inert to metal lithium, heated to 200 ° C., and preliminarily stirred at 50 rpm for 2 minutes. After stirring, the mixture was stirred at 230 ° C. at 200 rpm for 20 minutes, and the mixture was cooled to room temperature. The whole process was carried out in a glovebox with argon protection, the glovebox having a water content of less than 10 ppm and an oxygen content of less than 10 ppm. A lithium-carbon composite material was obtained. The results of the weighing test showed that the mass percentage of lithium in the lithium-carbon composite microparticles was 67.3%.

1 shows scanning electron microscope (SEM) images of acetyl black-carbon nanotube microsphere composites (a, b) and lithium-carbon composite microparticles (c, d) obtained in Example 1. FIG.

FIG. 2 is an enlarged view of the SEM image b of FIG. 1 (magnification: 20,000 times). The microparticles in the circle are carbon nanoparticles (ie acetylene-black nanoparticles).

Using a lithium-carbon composite material and a lithium sheet obtained as described above, a half cell [except 20 mg to 40 mg of the lithium-carbon composite microparticles obtained above, on a copper foam having a diameter of 1.5 cm and a thickness of 1 mm). Compressed, this material was used as negative electrode; A lithium sheet 400 μm thick and 1.5 cm in diameter was used as the positive electrode; Celgard membrane (film) is the positive electrode and negative electrode were prepared and combined becomes a yirum the coin battery of the 2025 type], the half cell cycle capacity under conditions of 0.5 mA · cm ^-2 and a current density of 0.5 mAh · cm ^-2 Characteristic tests were performed. FIG. 3 shows the results of the half cell cycle characteristic test, where the left plot is a cycle curve obtained when using lithium-carbon composite microparticles, and the right plot is a cycle curve of a lithium sheet. As can be seen from the figure, the lithium-carbon composite microparticles initially showed a very low polarization voltage compared to the lithium metal sheet, indicating that the specific surface area of the material is large, and the polarization voltage is significantly later in the cycle. This did not change, indicating that the material structure and the surface solid electrolyte interface (SEI) layer are stable.

Fig. 4 shows the electrode morphology of each of the half cells made of lithium-carbon composite microparticles and the half cells made of lithium sheets after 200 cycles under conditions of a current density of 0.5 mA cm ⁻² and a capacity of 0.5 mAh cm ⁻² . (A and b show images of the lithium-carbon composite microparticles, c and d show images of the lithium sheet). After the end of the cycle, for lithium sheets, dendrites were distributed throughout the sample surface, which would potentially pose a significant risk to the battery. In contrast, after the end of the cycle, the lithium-carbon micro-scale composite material sample remained in the particulate structure, which again demonstrates the stability of the present material structure during the cycle.

FIG. 5 shows the voltage-capacity curves of lithium-carbon composite microparticles / lithium half cells at different cycles during the constant current charge-discharge test (current density at 0.74 mA / cm ⁻² ). After 500 cycles with C-rate 1, the capacity of the lithium-carbon composite microparticles remained little changed, indicating that the surface SEI layer of the material was relatively stable during the cycle, and would not continue to consume metallic lithium.

Capacity retention rates at different cycles were measured at C-Rate 1 with a full cell of lithium-carbon composite microparticles and lithium iron phosphate, and a full cell of lithium sheet and lithium iron phosphate [but lithium-carbon composite microparticles 20 As a material obtained by compressing mg to 40 mg on a copper foam, a material having a diameter of 1.5 cm and a thickness of 1 mm was used as a negative electrode, and a lithium iron phosphate (LFP) electrode sheet (Sinzhou Battery Tech Co, Suzhou) Co., Ltd., using a surface density of 0.7 mAh / cm ² ) as a positive electrode, to produce a 2025 type coin battery] (in this case, the capacity of the positive electrode and negative electrode were 1.4 mAh and 40 mAh, respectively). 6 shows the test results. As shown in FIG. 6, the discharge capacity retention rate at the C-rate 1 after the completion of the 600th cycle of the full cell composed of lithium-carbon composite microparticles and lithium iron phosphate was 92.8%, whereas the lithium sheet was used as the negative electrode. The eggplant's capacity continued to decrease, and at the end of cycle 150, the capacity was nearly zero.

Example 2

A carbon nanotube microsphere material was prepared in the same manner as in Example 1 except that acetylene black was not used. The specific surface area of this microsphere material was 151 m ² / g and the average pore size was 18.7 nm. FIG. 7 shows a comparison of microsphere materials prepared without using carbon nanoparticles (left image) and microsphere materials prepared using carbon nanoparticles (right image). As can be seen from this figure, the morphology and structure of the microsphere material did not change significantly after the carbon nanoparticles were added.

Lithium-carbon composite microparticles were prepared using the carbon nanotube microsphere material in the same manner as in Example 1 except that the mass percentage of lithium in the lithium-carbon composite microparticles was 40.4%.

Under the conditions of a current density of 0.5 mA · cm ⁻² and a capacity of 0.5 mAh · cm ⁻² , the half-cell cycle characteristics of each of the obtained half-cells made of the lithium-carbon composite microparticles and the half-cells made of the lithium sheet The test was performed. 8 shows the results of the half cell cycle characteristic test. As shown in FIG. 8, in the case of a half cell made of lithium-carbon composite microparticles, the polarization voltage of the sample continued to increase as the number of cycles increased, which is due to the continuous reaction of the lithium metal with the electrolyte. This indicates that the SEI layer is getting thicker.

Example 3

The carbon nanoparticle-porous skeleton composite material and the lithium-carbon composite microparticles were prepared in the same manner as in Example 1 except that Ketjen black (ECP 600JD) was used instead of the acetylene black used in Example 1. Prepared. The mass percentage of lithium in the lithium-carbon composite microparticles was 60.0%. The morphology and property test results of the resulting material were similar to those of Example 1.

Example 4

The carbon nanoparticle-porous skeletal composite material and the lithium-carbon composite microparticles were subjected to the method of Example 1 except that Degussa carbon black (Printex XE-2) was used instead of the acetylene black used in Example 1. Prepared in the same manner. The mass percentage of lithium in the lithium-carbon composite microparticles was 51.8%. The morphology and property test results of the resulting material were similar to those of Example 1.

Example 5

2 g of carbon nanofibers (Alfa Aesar) and 2 g of acetylene black (Alfa Aesar) were added to 200 mL of deionized water, followed by 20 mL of anhydrous ethanol. The mixture was sealed, stirred and sonicated with a 130 W ultrasonic probe for 5 hours to uniformly disperse the sample. The sample was then introduced to a spray drier. The air inlet temperature was set to 200 ° C., the air outlet temperature was set to 150 ° C., the injection pressure was set to 40 MPa, and the sample size was set to 500 mL / h. After drying, an acetylene black-carbon nanofiber microsphere composite material having a morphology similar to the morphology of the acetylene black-carbon nanotube microsphere composite material of Example 1 was obtained. Nitrogen adsorption-desorption tests were performed on the composite material, and the results showed that the specific surface area of the microspheres was 98 m ² / g and the average pore size was 13.1 nm.

100 mg of battery-grade metal lithium and 100 mg of the acetylene black-carbon nanofiber microsphere composite were weighed, placed in a heater inert to metal lithium, heated to 200 ° C., and preliminarily stirred at 50 rpm for 2 minutes. After stirring, the mixture was stirred at 230 ° C. at 200 rpm for 20 minutes, and the mixture was cooled to room temperature. The whole process was carried out in a glovebox with argon protection, the glovebox having a water content of less than 10 ppm and an oxygen content of less than 10 ppm. Lithium-carbon composite microparticles were obtained. The results of the metering test showed that the mass percentage of lithium in the lithium-carbon composite microparticles was 36.3%. 9 shows an SEM image of a lithium-carbon fiber microsphere composite material (magnification of the left image is 1000 times and magnification of the right image is 25000 times).

10 shows a constant current charge-discharge curve from negative electrode lithium-carbon fiber microsphere composites. As can be seen from this figure, the polarization voltage of the lithium-carbon fiber microsphere composite was initially very low, which means that the specific surface area of the material is large, the current density is considerably reduced, and lithium dendrite formation can be effectively suppressed. Indicates that it could. Since the risk of potential short circuits caused by dendrites could be avoided, the material could be used substantially in high energy density battery systems.

Example 6

2 g of porous nickel metal skeleton material (pore size distribution of 100 μm to 500 μm, 1.5 cm in diameter, and 500 μm to 1000 μm in thickness) containing acetylene black (Alfa Aesar) at a concentration of 20 g / L The solution was placed in 100 mL of aqueous solution, and then subjected to sonication for 1 hour. The resulting mixture was left to stand and dried in an oven at 80 ° C. for 24 hours to obtain a porous nickel metal skeleton material containing carbon nanoparticles. The porous nickel metal skeleton material containing carbon nanoparticles was immersed in molten lithium metal to obtain a metal lithium-nickel skeleton material. Metering test results showed that the mass percentage of lithium in the metal lithium-nickel skeleton material was 50.0% [(mass of metal lithium-nickel skeleton material-mass of nickel metal skeleton) / mass of metal lithium-nickel skeleton material]. .

Half-cell cycle characteristics under conditions of a current density of 0.5 mA · cm ⁻² and a capacity of 0.5 mAh · cm ⁻² were tested for a half cell made of a metallic lithium-nickel skeleton carbon material. The result is shown in FIG. As can be seen from FIG. 11, the polarization voltage of the sample hardly changed after the end of the 200th cycle, but only a slight increase due to the gradual increase of the surface SEI layer thickness. In addition, the coulombic efficiency and stability of the capacity under full cell test conditions further indicated the stability of the material structure and surface SEI layer. Full cells consisting of metal lithium-nickel backbone carbon materials and lithium iron phosphate were tested for capacity retention at C-rate 1 in different cycles. The results are shown in FIG.

It is to be understood that the above description is only some preferred embodiments of the present invention and is not intended to limit the present invention. Any change made in the spirit and principle of the present invention, equivalents and modifications therein should be included within the protection scope of the present invention.

Claims (18)

The porous skeleton is a carbon-based porous microsphere material with a diameter of 1 μm to 100 μm, or a porous metal material having internal pores with a pore size distribution of micrometers, and the carbon nanoparticles are carbon-based porous microsphere materials or porous metal materials A carbon nanoparticle-porous skeleton composite material, characterized in that it is distributed on the inside and the surface of the pores. The method of claim 1, wherein the carbon-based porous microsphere material comprises at least one selected from the group consisting of carbon nanotubes or carbon nanofiber microsphere materials, graphite, mesocarbon microspheres, and porous activated carbon. Carbon nanotubes or carbon nanofiber microsphere materials are prepared by intertwining and agglomerating carbon nanotubes or carbon nanofibers, wherein the microspheres are filled with carbon nanotubes or carbon nanofibers within themselves, Multiple nano scale pores exist and / or on the inside and surface;
The porous metal material comprises at least one selected from the group consisting of porous copper, porous aluminum, porous zinc, porous iron, porous nickel, porous gold and porous silver;
And wherein the carbon nanoparticles comprise at least one selected from the group consisting of carbon black, acetylene black, Ketjen black, Timcal conductive additive Super P, and Cabot BP2000. Carbon nanoparticle-porous skeleton composite material according to claim 1 or 2, characterized in that the carbon nanoparticles can be 1 nm to 500 nm in size, preferably 50 nm to 200 nm. The carbon nanoparticle-porous skeleton composite material according to claim 1, wherein the content of the carbon nanoparticles is from 20 wt% to 500 wt% based on the porous skeleton. The method according to any one of claims 2 to 4, wherein the specific surface area of the carbon nanotube or carbon nanofiber microsphere material is from 100 m ² / g to 1500 m ² / g;
The pore size of the pores contained in the carbon nanotube or carbon nanofiber microsphere material is 1 nm to 200 nm;
The carbon nanotube or carbon nanofiber microsphere material has at least one selected from the group consisting of at least a coherent structure of a spherical entity, a spherical cohesion structure, a spheroidal cohesion structure, a porous spherical cohesion structure and a donut-like cohesion structure / Have;
The carbon nanotubes comprise any one selected from the group consisting of multiwall carbon nanotubes, double wall carbon nanotubes and single wall carbon nanotubes, or a combination of two or more thereof, optionally wherein the carbon nanotubes may have a surface action. A carbon nanoparticle-porous skeleton composite material, which is subject to vaporization treatment. Dispersing the carbon nanotubes or carbon nanofibers together with the carbon nanoparticles in a solvent to prepare a dispersion, and then spray drying the dispersion; or
Immersing microscale porous graphite, mesocarbon microspheres, porous activated carbon, or porous metal material in a solution containing carbon nanoparticles, followed by sonication, and then drying the resultant.
A method for producing a carbon nanoparticle-porous skeletal composite material according to any one of claims 1 to 5, comprising a. 7. The method of claim 6, wherein the spray drying the carbon nanotubes or carbon nanofibers with the carbon nanoparticles comprises the following steps:
a. Dispersing the carbon nanotubes / carbon nanofibers and carbon nanoparticles in a dispersion solvent (without surfactant) through sonication to obtain a dispersion;
b. Spraying the dispersion obtained in step a through the nozzle of a spray dryer which has a predetermined air inlet temperature and an air outlet temperature, provided that the dispersion is continuously stirred while spraying takes place; And
c. Cooling the result to obtain carbon nanoparticle-carbon nanotube / carbon nanofiber microsphere composites
Method comprising a. 8. The method of claim 7, wherein the mass ratio between carbon nanoparticles and carbon nanotubes / carbon nanofibers in step a is from 0.5: 1 to 8: 1;
The concentration of carbon nanotubes / carbon nanofibers in the dispersion is 10 g / L to 50 g / L;
The dispersion solvent comprises any one selected from the group consisting of water, aqueous ammonia, hydrochloric acid solution, ethanol, acetone and isopropanol or combinations thereof. The method of claim 7 or 8, wherein the air inlet temperature is 190 ° C to 210 ° C, and the air outlet temperature is 90 ° C to 110 ° C;
Spray rate is 1 mL / min to 100 L / min. The method of claim 6, wherein the solution containing carbon nanoparticles comprises an aqueous solution containing carbon nanoparticles;
The concentration of carbon nanoparticles in the solution containing the carbon nanoparticles is characterized in that from 5 g / L to 50 g / L. The carbon nanoparticle-porous skeleton composite material according to any one of claims 1 to 5, wherein the metal lithium is distributed on the inside and the surface of the pores of the carbon nanoparticle-porous skeleton composite material. , Metal lithium-carbon nanoparticle-porous skeletal composite material. 12. The lithium-carbon nanoparticle-porous skeleton composite material of claim 11, wherein the metal lithium is present in an amount of 1% by mass to 95% by mass based on the total mass of the lithium-carbon nanoparticle-porous skeleton composite material. . A metal lithium-carbon nanoparticle-porous skeleton composite, comprising mixing the carbon nanoparticle-porous skeleton composite material according to any one of claims 1 to 5 with molten lithium metal and then cooling the mixture. Method for manufacturing the material. The method of claim 13, wherein the mixing of the molten lithium metal and the carbon nanoparticle-carbon based porous microsphere composite material
Mixing the lithium metal and the carbon-based porous microsphere material with stirring, followed by heating; or
Immersion of Carbon Nanoparticle-Porous Metal Composites in Molten Lithium Metal
Method comprising a. 15. The method of claim 14, wherein the stirring and mixing comprises a preliminary stirring step and a rapid stirring step, provided that the preliminary stirring step comprises mixing the mixture of lithium metal and carbon nanoparticle-porous skeletal composite material at a rate of 50 rpm to 100 rpm. Stirring for 1 minute to 5 minutes at 200 ° C. to 230 ° C., wherein the rapid stirring step comprises rapid agitation at 230 ° C. to 300 ° C. at a rate of 150 rpm to 1000 rpm. An electrode comprising the lithium-carbon nanoparticle-porous framework composite material according to claim 11. An electrochemical energy storage device comprising the electrode according to claim 16, wherein the electrochemical energy storage device comprises an electrochemical battery or a super capacitor. 18. The electrochemical energy storage device of claim 17, wherein the electrochemical battery comprises a lithium battery, a metal lithium-oxide battery, a metal lithium-sulfur secondary battery, or a metal lithium-air battery.

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